// Copyright (c) 2011 Sundog Software LLC. All rights reserved worldwide.

Shader "Particles/Stars No Fog" {
Properties {
 _MainTex ("Particle Texture", 2D) = "white" {}
 _InvFade ("Soft Particles Factor", Range(0.01,3.0)) = 1.0
}

Category {
 Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
 Blend SrcColor One 
 ColorMask RGB
 Cull Off Lighting Off ZWrite Off Fog { Mode Off }
 BindChannels {
     Bind "Color", color
     Bind "Vertex", vertex
     Bind "TexCoord", texcoord
 }
 
 // ---- Fragment program cards
 SubShader {
     Pass {
     
         CGPROGRAM
         #pragma vertex vert
         #pragma fragment frag
         #pragma fragmentoption ARB_precision_hint_fastest
         #pragma multi_compile_particles

         #include "UnityCG.cginc"

         sampler2D _MainTex;
         fixed4 _TintColor;
         
         struct appdata_t {
             float4 vertex : POSITION;
             fixed4 color : COLOR;
             float2 texcoord : TEXCOORD0;
         };

         struct v2f {
             float4 vertex : POSITION;
             fixed4 color : COLOR;
             float2 texcoord : TEXCOORD0;
             #ifdef SOFTPARTICLES_ON
             float4 projPos : TEXCOORD1;
             #endif
         };
         
         float4 _MainTex_ST;

         v2f vert (appdata_t v)
         {
             v2f o;
             o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
             #ifdef SOFTPARTICLES_ON
             o.projPos = ComputeScreenPos (o.vertex);
             COMPUTE_EYEDEPTH(o.projPos.z);
             #endif
             o.color = v.color;
             o.texcoord = TRANSFORM_TEX(v.texcoord,_MainTex);
             return o;
         }

         sampler2D _CameraDepthTexture;
         float _InvFade;
         
         fixed4 frag (v2f i) : COLOR
         {
             #ifdef SOFTPARTICLES_ON
             float sceneZ = LinearEyeDepth (UNITY_SAMPLE_DEPTH(tex2Dproj(_CameraDepthTexture, UNITY_PROJ_COORD(i.projPos))));
             float partZ = i.projPos.z;
             float fade = saturate (_InvFade * (sceneZ-partZ));
             i.color.a *= fade;
             #endif
             
             return i.color * tex2D(_MainTex, i.texcoord) * i.color.a;
         }
         ENDCG 
     }
 }   

 // ---- Dual texture cards
 SubShader {
     Pass {
         SetTexture [_MainTex] {
             combine primary * primary alpha
         }
         SetTexture [_MainTex] {
             combine previous * texture
         }
     }
 }
 
 // ---- Single texture cards (not entirely correct)
 SubShader {
     Pass {
         SetTexture [_MainTex] {
             combine texture * primary
         }
     }
 }
}
}


